Domain of $f\left(x\right)={\sin }^{-1}x+{\sec }^{-1}x$ is

Domain of ${\sin }^{-1}x$ is [-1, 1] and domain of ${\sec }^{-1}x$ is R - (-1, 1)

$\therefore$Domain of ${\sin }^{-1}x+{\sec }^{-1}x$ is $[-1,1]\cap R-(-1,1)=\{-1,1\}$